The transplantation of hair grafts into a human scalp is well understood. The present state of the art calls for excising a hair-rich area of the scalp, dissecting the excised scalp segment to obtain individual grafts for implantation, creating an implantation site in a bald area of the scalp and implanting an individual graft into the prepared implantation site. It is also known that a preferred graft for implantation comprises a follicular unit which is the basic microscopic anatomy which contains 1–4 hairs bunched together.
Implantation instruments for use by a surgeon to implant hair grafts are well known. For example, U.S. Pat. No. 6,059,807, issued May 9, 2000 discloses a hair graft implantation instrument which includes a hollow needle which is moved within a sheath between first and second positions at which the needle extends beyond the sheath and at which the needle is retracted within the sheath. In operation, a vacuum is created within the needle when it is advanced to the first position to grasp a graft for implantation. The needle is inserted into a scalp as the vacuum is released. The needle is spring loaded to retract the needle to the second position.
The instrument disclosed in U.S. Pat. No. 6,059,807 is delicate to control requiring adjustment to position the needle tip to capture a graft. Moreover, implantation of a graft is difficult to achieve because of frequent removal of an implanted graft as the needle is withdrawn.
U.S. Pat. No. 6,461,369B1 issued Oct. 8, 2002 also discloses an instrument for hair graft implantation. The instrument disclosed in U.S. Pat. No. 6,461,369Bi comprises a needle with a slot for securing a hair to which a root is attached. The instrument also includes a sliding member which forms a sheath about the needle. The needle is inserted into the scalp and the surgeon depresses the sliding member towards the scalp as the needle is withdrawn, the sliding member operating to retain the graft in place. This instrument also requires a significant amount of training to coordinate the withdrawal of the needle and the manipulation of the sliding member.